String.Format custom parameter placeholders

Question

I have a string var str1 = "My name is {{0}}, I am {{1}} years old." I want to use String.Format(str1, 'Pavel', 29);

Of course it does not work, because String.Format() expects parameter placeholders to be in a single curly brackets

So, I have to modify my string like that:

for (int i = 0; i < 10; i++)
{
    str1 = str1.Replace("{{" + i + "}}", "{" + i + "}");
}

I wonder if there is a better way of doing it ? Is there a way I can define the format of the argument placeholders ?

Why does the original str1 have double braces in it to begin with? Is it supplied to you from somewhere you do not control? — Mike
– Mike, Commented Jan 24, 2018 at 17:41

Patrick Hofman · Accepted Answer · 2018-01-24 16:28:03Z

1

Is there a way I can define the format of the argument placeholders?

No.

I wonder if there is a better way of doing it?

The only option you have is to make a format string that is compatible with string.Format. And that is what you have done now. If you can, fix the origin of those format strings.

If that is not possible, I would opt to use a regular expression to make this more robust and better performing.

The expression you should use is {{(\d+)}}, which can be replaced with {$1}. See it in action here.

edited Jan 24, 2018 at 16:28

answered Jan 24, 2018 at 16:11

Patrick Hofman

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